A collaborative paper was just out in Soil Biology and Biochemistry. Rose Abramoff led the paper and Xu participated in the development of the Millennial model.

Abramoff, R.Z.*, Guenet B., Zhang H.C., Georgiou K., Xu X.F., Viscarra Rossel R.A., Yuan W.P., Ciais P. (2022) Improved global-scale predictions of soil carbon stocks with Millennial Version 2. Soil Biology and Biochemistry, 164,108466.  

https://www.sciencedirect.com/science/article/pii/S0038071721003400?via%3Dihub

A NSF RAPID project was funded to support the further improvement and application of the Millennial model. Dr. David Lipson is the lead PI, Xu serves as a Co-I. The Millennial model will be combined with the CLM-Microbe model to investigate the drought and fire impacts on vegetation phenology and soil microbial processes and carbon cycles.

https://www.nsf.gov/awardsearch/showAward?AWD_ID=2154746&HistoricalAwards=false